1. Field of the Invention
The present invention relates to a method and apparatus for displaying a tree structure diagram representing a relation among windows prepared for assisting a computer operation, and more particularly to a method and apparatus for displaying a tree structure diagram for windows which tree structure diagram is provided with icons which graphically indicate the contents of respective windows.
Such display of the tree structure diagram of windows is particularly helpful as a tool for developing programs of multi-window systems operated with a graphical user interface. Each window in the multi-window system has a parentage (parent-child relationship). It is important to easily recognize the parentage of windows over an entire multi-window system when developing the multi-window system.
2. Description of the Related Art
FIG. 1 is an illustration of a screen displayed by a first conventional system in which information regarding each window can be displayed. FIG. 1-(A) shows a current window displayed on the screen; FIG. 1-(B) shows a display presenting a parentage between the current window and the selected one of windows provided in the current window. When the level of the window having a title "List 1" in the current window shown in FIG. 1-(A) is searched, the window "List 1" in the current window is clicked by a mouse. By doing this, information including the parentage of the window "List 1" is displayed as shown in a table in FIG. 1-(B).
However, the above-mentioned first conventional system displays information with respect to only the window currently being focused. Thus, although the title of the parent window can be displayed, it is difficult to recognize a relation between the focused window and other windows. Accordingly, in order to obtain the parentage among all windows, each of the windows must be opened by clicking by a mouse. This is inconvenient and requires a considerably long time. Additionally, it is difficult to know the function of each of the windows without executing the program designated by each of the windows.
FIG. 2 is an illustration of a screen displayed by a second conventional system in which information regarding each window can be displayed. FIG. 2-(A) shows a current window displayed on the screen; FIG. 2-(B) shows a display presenting information of a list of windows provided in the current window. The display of FIG. 2-(B) is displayed on the screen by clicking the corresponding window provided in the current window.
This system merely displays the contents of the focused window, and it is not possible to recognize a parentage among the windows.
Japanese Laid-Open Patent Application No. 2-171917 discloses a multi-window control system in which information regarding a parentage among windows is included. This system automatically manages hierarchy information including parentage information. A list of a plurality of windows is displayed on the screen in accordance with the hierarchy information. In this system, the parentage is managed by a title and an identifier representing the hierarchy information which is provided to each window. The identifier of each of the windows is displayed together with the title in the form of a list table on the screen so that a desired window can be selected. The list of the windows is displayed as shown in FIG. 3.
In FIG. 3, the window corresponding to an identifier "a" is at the highest level. That is, in FIG. 3, the window having a title 1 is the highest order window. Windows having lower order are sequentially displayed in the order from a higher order to a lower order. That is, for example, the window having a title 2, which corresponds to an identifier "a.a", is a direct child of the window having the title 1. The window having a title 3, which corresponds to an identifier "a.b", is also a direct child of the window having the title 1, and is also a brother of the window having the title 2. Apparently, the window having a title 4, which corresponds to an identifier "a.a.a" is a child of the window having the title 2. In this way, the entire parentage among the windows can be observed.
According to the above-discussed conventional system, since the hierarchical relation between the windows is displayed with only the title of each window, it is difficult to know the function of the windows having a parentage.
Japanese Laid-Open patent Application No. 1-276194 discloses another multi-window display system which can provide information regarding a parentage between windows. In this system, as shown in FIG. 4, the contents of child windows can be displayed with the current window which is a parent window. The contents of the child windows are displayed in an overlapped relation with the respective parent window with lines connecting the corresponding window in the respective parent windows. This provides a visual display of the parentage among the windows. Additionally, this system can display a function of each child window by character strings.
As discussed above, this conventional system can display the parentage in a visual manner in which the parentage can be easily recognized. However, the information of each window is displayed by character strings. Thus, there is a problem in that it is difficult to quickly recognize the function of each window only by the character strings.